Field of the Invention
The present invention relates to an electrophotographic photosensitive member, and a process cartridge and an electrophotographic apparatus each including the electrophotographic photosensitive member.
Description of the Related Art
An electrophotographic photosensitive member containing an organic photoconductive material (charge generating material) has been mainly used as an electrophotographic photosensitive member to be mounted onto a process cartridge or an electrophotographic apparatus. The electrophotographic photosensitive member generally includes a support and a photosensitive layer formed on the support. Further, an undercoat layer is often formed between the support and the photosensitive layer.
A requirement for image quality has been continuing to grow in recent years. For example, an allowable range for color reproducibility has started to become much narrower.
The light portion potential of the electrophotographic photosensitive member is one important factor for the color reproducibility. In particular, when the potential largely fluctuates at the time of output on a large number of sheets, the color reproducibility changes and hence the image quality reduces.
Not only at the time of full-color output but also at the time of monochrome output, the fluctuation in potential causes, for example, a change in density of a halftone image and hence leads to the reduction in image quality.
A technology involving incorporating an electron transporting material into the undercoat layer has been known as a technology for the suppression (reduction) of such fluctuation in potential at the time of the output on a large number of sheets.
In each of, for example, Japanese Patent Application Laid-Open No. 2001-83726, Japanese Patent Application Laid-Open No. 2003-345044, and Japanese Patent Application Laid-Open No. 2008-65173 as the technology involving incorporating the electron transporting material into the undercoat layer, there is a disclosure of a technology involving incorporating the electron transporting material, such as a fluorenone compound derivative, an imide compound derivative, or an anthraquinone derivative, into the undercoat layer.